HISTORY OF ZOOPHYTOLOGY. 29 



iiig that they have no animal structure or individual organs, and 

 exhibit no one function usually supposed to be characteristic of 

 that kingdom. Like vegetables they are permanently fixed, — 

 like vegetables they are non-irritable, — their movements, like 

 those of vegetables, are extrinsical and involuntary, — their nu- 

 Iriment is elaborated in no appropriated digestive sac — and like 

 cryptogamous vegetables or algae they usually grow and ramify 

 in forms determined by local circumstances, and if they present 

 some peculiarities in the mode of the imbibition of their food 

 and in their secretions, yet even in these they evince a nearer 

 affinity to plants than to any animal whatever. 



